Which is better, a smart card or a USB token?
IdenTrust has selected smart card and USB devices that are FIPS 140 level 2 that comply with the security requirements outlined in the ECA Certificate Policy. Both devices provide 32KB of memory that exceed your storage needs for ECA certificates. Both devices are comparable and you can use either one without any concerns.
To make your final decision, you should consider other factors such as portability and your level of comfort using either technology.